Abstract: By taking instantaneous eigenstates as complete base vectors,a traditional time-dependent magnetic Schrodinger equation is transformed into a second-order differential equation with constant coefficient which can be solved exactly.The difference between accurate solution and adiabatic solution of the magnetic resonance system is studied,our results show that the tunneling rate can not be always ignored.When the rotating magnetic field adjustable parameter θ is equal to 0.304 3π,the tunneling rate can be increased to the maximum value of 0.111 1.

Key words: magnetic resonance, quantum adiabatic theorem, instantaneous eigenstate